ABSTRACT
Barriers to entry as economic idea is full of curiosities, Bain was the founder of Harvard School but worked his whole life at Berkeley University, California. The reintroduction of litigation cases in the analysis of competition could be considered a new way to demonstrate his premises, keeping in mind that, at this time, the traditional Harvard School used to confirm the hypothesis with cross-section data. The traditional Chicago School, or neoclassical theory, used models of the competitive firm, which means markets function freely, price and technology are known by bargains, with both firms and customers, and owners effectively controlling the use of their assets. The Harvard tradition tried to offer a scientific model able to demonstrate that the rules of free market do not work as well as would be expected. One of the most stimulating methodological debates within Industrial Organization is that between the Harvard School and the Chicago School, largely because Chicago has always preferred models taken from Microeconomics.
